Attachment for material handling lift trucks



5 Sheets-Sheet 1 T. H. BARTEL ET AL ATTACHMENT FOR MATERIAL HANDLING LIFT TRUCKS Aug. 9, 1955 Filed Dec. 28, 1949 Aug. 9, 1955 T. H. BARTEL ET AL ATTACHMENT FOR MATERIAL HANDLING LTRT TRUCKS Filed Dec. 28, 1949 5 Sheets-Sheet 2 Ri 5 Wwf Mn. HW? f i MMM Aug. 9,

Filed Dec. 28, 1949 T. H. BARTEL ET AL ATTACHMENT FOR MATERIAL HANDLING LIFT TRUCKS 5 Sheets-Sheet 3 INVENTOR. TOM f/. Aena ANDR W J. MEAD Aug. 9, 1955 T. H. BARTEL ET AL ATTACHMENT FOR MATERIAL HANDLING LIFT TRUCKS Filed Dec. 28, 1949 5 Sheets-Sheet 4 33 Z0 m44 .7753/ DB2/ Aug. 9, 1955 ATTACHMENT FOR MATERIAL HANDLING LIFT TRUCKS Filed Dec. 28, 1949 a Elck-11E 5 Sheets-Sheet 5 www@ nited States Patent O ATTACHMENT FOR MATERIAL HANDLING LIFT TRUCKS Tom H. Bartel, Andrew J. Meade, Paul E. Smith, and Herbert C. Tims, Detroit, Mich., assignors to Clark Equipment Company, Buchanan, Mich., a corporation of Michigan Application December 28, 1949, Serial No. 135,458

28 Claims. (Cl. 214-653) This invention relates to article handling attachments primarily designed to be mounted upon a conventional type lift truck.

The invention essentially consists in the provision of an attachment of this type adapted to be connected to the elevating mechanism of a lift truck and incorporating a load engaging means consisting of the combination of an improved pressure operated article grabbing device adapted to engage one surface on the article and a backplate adapted to engage another surface on the article. Improved mountings for the attachment also form a part of the invention, including a pivotal type of mounting which, when employed in combination with a member or members whose function is to make initial contact with the article for centering or aligning the grabbing device of the attachment to engaging position, makes it possible to engage an article from all reasonable angles of approach of the lift truck thereto and eliminates the necessity for maneuvering the truck into one proper engaging position. This form of mounting preferably includes centering means for controlling the pivotal movement of the attachment about its pivotal axis and automatically returning it to a position in substantial alignment with the longitudinal axis of the truck. All forms of the invention preferably include a form of safety device to prevent the article from becoming disengaged i from the attachment during the period it is elevated by the mechanism of the lift truck.

The article-grabbing device is preferably of a type which engages the article from above, since this type offers many advantages in article handling over conven- I' tional forks or side-engaging grabs. The constructions disclosed and to be more fully discussed herein illustrate embodiments of the invention in attachments particularly designed for handling newsprint rolls or cylindrical objects having a center core, and in an attachment designed for handling boxes, crates or other rectangular or cubicle objects.

The first of these attachments is illustrated in Figs. 1

to 8 of the drawings, the second is shown in Figs. 9 and 10, while a third is depicted in Figs. 11 to 14, these views being individually identified as follows:

Fig. 1 is a side elevation of a single attachment centrally located at the front end of a lift truck, that portion of the truck being shown in phantom. The outboard mounting cylinder identified by the reference 13a in Fig. 2 has been omitted from this View for the sake of clarity;

Fig. 2 is a plan view of the attachment shown in Fig. 1;

Fig. 3 is a sectional elevation taken along the line 3--3 of Fig. 2;

Fig. 4 is a sectional view of the mounting for the safety device taken along the line 4-4 of Fig. 1;

Fig. 5 is a sectional View taken along the line 5--5 of Fig. 1;

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 1;

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Fig. 7 is a sectional view taken along the line 7--7 of Fig. 3;

Fig. 8 is a sectional view taken along the line 8-8 of Fig. 3;

Fig. 9 is a side elevation of an attachment incorporating the improved construction of the article grabbing device of the invention in combination with an improved construction of back plate and article contacting members, the attachment being constructed for rigid mounting upon a lift truck;

Fig. 10 is a plan view of the attachment shown in Fig. 9;

Fig. 1l is a side elevation of an attachment designed for handling box-like articles;

Fig. 12 is a plan view of the construction shown in Fig. 11;

Fig. 13 is a sectional view taken along the line 13-13 of Fig. 11; and

Fig. 14 is an enlarged detail showing the construction and attachment of the article-engaging prongs.

The attachment of Figs. 1l to 14 is not shown in its association with a lift truck since this is in all ways similar to that illustrated and described for the attachment of Figs. 1 to 8.

With reference to Figs. 1, 2 and 3, it will be seen that a vertical base plate 10 for the attachment is connected to the movable member 11 of the mast 12 of a lift truck, the front portion of which is shown in Fig. 1 only. Welded to the front side of the plate 16 are three generally cylindrical tubes 13a, 13b and 13C, which are mounted in a vertical position. As best shown in Fig. 3, a cylindrical shaft 14 extends completely through the cylinder 13b with sutcient clearance to permit free rotation of the shaft 14.

The position of the shaft 14 within the tube 13b is defined by an upper semicylindrical collar 18 and a lower semicylindrical collar 28, these collars being bolted to the shaft 14 and to an arcuate backplate 26 by upper bolts 16 and lower bolts 27. Struts 29 and 30 extend between the backplate 26 and upper collar 18 and lower collar 28, respectively, to aid in establishing a firm, rigid connection between the backplate and collars. This `construction and relationship of parts is shown in detail in Figs. 5 and 6.

A plate 15 is welded to the upper collar 18 and upper surface of the backplate 26 and extends at right angles to the longitudinal axis of the shaft 14 to serve as a support for a cylindrical tubular guide member 17 which is connected thereto with the aid of a strap 31 connected to the plate 15 by bolts 23.

The forward half of the upper end surface of each of the tubes 13a, 13b and 13e` is tapered downwardly, as shown at 21, and provided with a centrally located notch 22, as most clearly shown in Fig. 8; While the lower end surface of the upper collar 18 is provided with a hardened detent 19, which, when in engagement with the notch 22, fixes the center line of the device in substantial parallelism with the longitudinal center line of the truck to which it is attached. The slope of the tapered portion 21 and depth and contour of the notch 22 are adapted to permit rotational torque from side pressure on the attachment to move the detent 19 out of the notch 22 and up the slope 21 in order to permit pivotal rotation of the shaft 14 and the attachment as a whole connected thereto, as well as to cause the Weight of the attachment alone or in combination with any load carried thereby to automatically rotate the attachment to a central position where the stop 19 engages the notch 224. Notch 22, while suiciently deep to prevent any swinging of the attachment and load as a result of ordinary maneuvering of the truck, is at the same time proportioned so that lateral forces on the attachment, in excess of those encountered in normal maneuvering, will be sufficient to disengage the detent 19 from the notch 22 in order to permit the attachment to be self-centering with respect to any load engaged from a misaligned position, as will be hereinafter explained in fuller detail.

As best shown in Figs. 3, 5 and 6, a curved, iiexible sheet metal plate Vis also secured to the shaft 14 by the upper bolts 16 and lower bolts 27, this sheet metal plate 25 being formed as a substantially cylindrical segment having a radius of curvature slightly smaller than the radius of the smallest cylindrical objects designed to be carried by the attachment.

The article-grabbing device employed for the handling of paper rolls is similar in principle to that disclosed in Patent No. 1,377,978 issued May l0, 1921, and consists of a plug or article engaging member adapted to be inserted within the core 42 of a roll of paper 43, as illustrated in Fig. 3. This plug is formed with a flattened upper end 34 which is mounted within the slotted portion 33 of a pistonlike member 32 and connected thereto by a pin 31. The pistonlike member 32 is slidably tted within the bore of the tubular guide member 17, the lower side wall of which is slotted as indicated at 37 to receive the flattened end 34 of the plug. The assembly is completed by a cylindrical cap 36 connected to the outer end of the slotted portion 33 of the pistonlike member by bolts 24.

Sliding movement of this assembly, and plug 35 carried thereby, longitudinally of the guide tube 17 is in response to the actuation of a hydraulic cylinder 39 having its head end anchored to the shaft 14 by a pin 40 and its piston rod 38 threadedly connected to the piston 32. This cylinder is centered within the bore of the tube 17 by a ring 41, and a slotted aperture 70 is formed in the upper wall of the tube 17 for the connection of hydraulic lines 44 and to the rod and head ends of the cylinder respectively.

Preparatory to engaging a roll, the plug 35 is moved to its outermost position by introduction of fluid pressure through the fitting 45 at the head end of the cylinder 39, and the hoist mechanism of the truck is moved up to a position where the plug 35 will clear the top of the roll 43. When the truck is then moved toward a roll the plate 25 will contact the outer perimeter of the roll and center the attachment in a position where the plug 35 is directly above the core 42. If the truck is misaligned with the roll as it approaches the same, one or the other of the ends 46a or 46b of the plate 25 will first contact the side of the roll, exerting a lateral force or torque about the axis of the shaft 14 sufficient to disengage the detent 19 from the notch 22 and to rotate the attachment in the direction required in order to center the plug 35 above the core 42. The hoist mechanism of the truck is then moved down until the plug 35 is at an engaging level, as shown in Fig. 3, whereupon the liuid pressure cylinder 39 is actuated by introducing fluid through line 44 to the rod end of the cylinder to draw the plug 35 and roll engaged thereby into firm frictional engagement with the positioning plate 25 and backplate 26. In the case of newsprint rolls wound upon cardboard or fibre cores, it has been found preferable to design the plug 35 so that the longitudinal axis of its cylindrical portion extends at an angle to the axis of the roll being engaged, as shown, thus giving a finger-gripping action to the plug which augments the frictional engagement between the roll and parts of the device contacted thereby, and also tending to prevent the metal insert 20 used at each end of the core for mounting the roll on the spindles of a press from being damaged by the insertion and withdrawal of the plug 35 into the core. After thus engaging a roll with the device, the former can, with the aid of the conventional mechanism of the lift truck, be raised, lowered, transported, tiered or put through any of the usual handling operations for which lift trucks are employed.

A safety foot 48 carried by a shaft 49 forms a part of the device and is adapted to be rotated into position under an engaged roll after such roll has been lifted from its .supporting surface, as previously described. The shaft 49 is rotatably mounted within an upper bracket 51 and lower bracket which are attached to the backplate 26. Shaft 49 is connected to an upper collar 52, the lower end 52a of which rides against the upper surface of bracket 51, by a key 58 engaging an extended slot 59 in the shaft. The shaft is also connected to a lower collar 60 by a pin 61 which can be engaged in any one of a number of alternative holes 62 to vary the operating level of the safety foot 48. Actuation of the safety foot is accomplished through the operation of an actuating cylinder 54, having its head end secured by a bracket 55 to a plate 53 carried by the plate 15, and its piston rod 56 connected by a pin 57 to a crank 63 formed as part of the upper end of the collar 52. Rotation of the collar 52, produced by operation of the actuating cylinder, causes rotation of the shaft 49 through the keyed connection previously mentioned.

When the attachment is initially lowered to an engaging position, the foot 48 will contact the floor and move the 4shaft 49 longitudinally upwards as permitted by the elongated keyway 59 and the space between the upper bracket 51 and lower collar 60. When the load is raised,

'i the shaft 49 will drop down to a position defined by the engagement of the lower collar 60 and bracket 50 where the foot 48 is below the bottom edge of the roll, whereupon the cylinder 54 may be actuated to turn the foot 48 into an operative or blocking position. Alternative holes 62 through the shaft 49 permit adjustment of the lowermost level to which the foot 48 will move in accordance with variations in the lengths of rolls to be handled by the attachment. When a roll is to be deposited, the cylinder54 will be actuated to move the foot 48 to an inoperative position, whereupon the roll may be lowered to floor level and disengaged by reversing fluid pressure to the actuating cylinder 39.

Where it is desired to handle two rolls at once, attachments identical to that discribed above and shown in the central position at cylinder 13b may be mounted in the outer cylinders 13a and 13C (see Fig. 2).

The embodiment of the invention shown in Figs. 9 and l0 incorporates the improved type of roll-grabbing device of Figs. l to 8 in combination with a modified construction of article engaging members and backplate and a fixed, rather than pivotal centering mounting of the attachment as a whole. Since the construction of the grabbing or core-engaging device used in this embodiment is identical to that previously described, the various parts of this assembly have been referenced with numerals corresponding to those used in Figs. l to 8, and the previous description of the construction and functioning of these parts is applicable here. This grabbing-device assembly, comprising all the parts mounted within the guide tube member 17, is supported upon a plate 64 extending horizontally from a main vertical mounting plate 65, and the end of the actuating cylinder 39 of the assembly is connected to a clevis 66 on the plate 65 by a pin 67. A pair of upper and lower brackets 68a and 68b extend forwardly and outwardly from each side of the plate and an article engaging member in the form of a roller 69 is mounted vertically between the outer ends of each pair of brackets.

Backplate 10Q extends between each pair of brackets 68a and 68h. At the point of attachment between the backplate and each bracket the material of the backplate is bent to form an attaching lug 101 which also serves to position the article-engaging surface of the backplate outwardly from the supporting brackets and so-that a line drawn as an extension of the arcuate backplate surface would be substantially tangent to the'periphery of the engaging rollers 69. Due to the fact that the backplate is not supported or based at its center, it, as well as the mounting brackets 68a and 68b, possess suiiicient flexibility so that that article-engaging surface of the backplate will accommodate itself to the contour of a roll within the variance in roll diameter normally encountered, and it can be seen that, when a roll is engaged by the plug 35 and squeezed against the backplate, the curvature thereof may decrease or increase with a corresponding inward or outward movement of the outer ends of the mounting brackets 68a and 68h. The attachment as a whole is secured in a conventional manner to the vertical movable member 102 of a lift truck 103.

The form of construction illustrated in Figs. 9 to 12 is included to show one of the many possible alternative forms of the invention, adapting the feature thereof to a device for handling objects of other sizes and shapes than cylindrical rolls. This particular form has been designed for engaging and handling rectangular objects such as boxes and crates and is attached to a lift truck in the same manner as the rst form of device previously described through a suitable mounting plate 71, shown in phantom. Rigidly secured to this mounting plate with the aid of supporting struts 72 is a cylinder 13d which is similar in all respects to the mounting cylinder 13b previously described. Shaft 73 is rotatably mounted within the cylinder 13d and xed therein by an upper collar 74 and lower collar 7S. These collars are similar in construction to the upper collar 18 and lower collar 28, and are secured to the shaft 73 by bolts 76 passing through the shaft, the collar and a backplate 77. Additional bracing in the form of struts 78 is employed to rigidly attach the backplate to each of the collars so that the backplate 77 and shaft 73 are rotatably mounted within the cylinder 13d.

Centering means for controlling this rotation is employed similar to that used on the first form of attachment and consisting of a tapered surface 79 and notch 80 formed on the upper end of the cylinder 13d and a detent 81 on the lower face of the upper collar 74.

The article-grabbing device consists of a pair of guideways 82 rigidly secured to the backplate 77 and each mounting a slide 83. The slides 83 are connected by a cross member 84, the connection being established by a headed bolt 85 fastened to the slide 83 and engaging a slot 86 in the cross member 84. An actuating cylinder 87 is pivotally connected to the cross member 84 through its clevis 88 and has its piston rod 89 connected by a bolt 90 to the shaft 73. A plate or linger 91 extends downwardly from the outer end of each slide 83 and is provided with a series of points or prongs, which are standard article handling aids, consisting of a pointed end 92 and threaded shank 93 for establishing a connection to the plate 91, as shown in Fig. l2. Similar points 95 are secured to the backplate immediately below the guideways 82. A vertical roller 94 is mounted at each side of the backplate between a pair of resilient brackets 96.

If desired, a safety foot similar to that previously described can be employed on this construction.

With this form of device attached to a lift truck, its operation parallels that of the roll handling device. With the device elevated by the mechanism of the lift truck to a height suilcient to clear the top of the article to be handled, the truck can be driven up to the article from any reasonable angle of approach. If the longitudinal cen-4 ter line of the truck is not perpendicular to the side of the article being approached, one of the rollers 94 will rst contact the article and cause the device to rotate to a properly aligned position where the backplate 77 engages the side of the article. The device is then lowered slightly to drop the plates 91 over the opposite side of the article and then fluid pressure is applied to the actuating cylinder 87 to move the slides 83 towards the backplate and thus place the article in rm engagement between the backplate and the plates 91. As the attachment, and article engaged thereby, are raised olf the supporting surface by the mechanism of the lift truck, the attachment will automatically center into alignment with the longitudinal axis of the truck by the action of gravity on the tapered surface 79 of the tube 13d, and will be maintained in such alignment by the engagement between the detent and notch. This centering feature of the invention, which results from providing a vertically pivoted means for initially engaging the load, together with some means for automatically returning the engaging means to a centered position, has a great ellect upon the speed with which articles can be handled in a lift truck operation, since it not only eliminates the necessity for accurately aligning the truck with the load, but also makes it possible to easily engage loads where a small amount of operating space is available, such as, for example, in removing the iirst few articles from a box car.

The forms of article-grabbing device employed herein are brought into engagement with the load from above. While this is not considered a limiting factor, this type of article-grabbing device has considerable commercial advantage in that it eliminates the necessity of mounting a load on pallets for handling purposes and thus simp'lies all operations connected with the handling of articles, as well as the amount of space required for the storage thereof. Pallets, of course, mean additional expense, require additional storage space and additional maintenance, while side-engaging grabs require more storage space in order to provide access to each article.

We claim:

l. In an article handling device for a vehicle such as a lift truck, means providing a vertical pivotal axis, aligning means adapted to contact the surface of an article to be handled on at least one location spaced above the supporting surface on which said article rests and spaced to one side of said pivotal axis, means supporting said aligning means for pivotal movement about said axis in response to such contact, and grab means initially positionable relative to the article by such pivotal movement of said aligning means for engaging said article after alignment of said device therewith.

2. An article handling device according to claim 1 further including means for normally urging said aligning means to one position of movement about said pivotal axis.

3. An article handling attachment according to claim l further including means supporting said grab means for movement relative to said aligning means, and means for moving said grab means to engage an article between said grab means and said aligning means.

4. An article handling device according to claim l wherein said aligning means comprises a backplate, with article contacting means carried by said backplate at laterally spaced positions to either side of said pivotal axis.

5. An article handling device according to claim 4 wherein the article contacting means carried by said backplate are resilient relative thereto.

6. An article handling attachment according to claim l wherein said grab means include a support mounted above the level of said aligning means, a grab member movably carried by said support and depending therefrom, said grab member being adapted to engage a surface of said article disposed oppositely to the surface contacted by said aligning means, and means for moving said grab member towards and away from said aligning means whereby an article can be engaged therebetween.

7. An attachment according to claim 6 wherein said depending grab member extends at an angle toward said aligning means.

8. An article handling attachment for a vehicle such as a lift truck, said attachment comprising a member for engaging a side surface of the article to be handled, a member for engaging a second surface disposed oppositely to said side surface, means for moving said members towards and away from each other, and further including means for mounting said article engaging members on a vertical axis for pivotal movement in unison relative to 7 said vehicle in response to contact between an article and one of saidv article engaging members.

' 9. An attachment for a -vehicle such as a lift truck adapted to handle cylindrical rolls having an open core, said attachment comprising a member for engaging a portion of the outer surface of a roll, a member for engaging the core of a roll, mechanism for moving said members towards and away from each other, said attachment including means for mounting said roll engaging members for pivotal movement in unison relative to said vehicle about a vertical axis in response to contact between a roll and said member for engaging the outer surface thereof.

10. An attachment as set forth in claim 9 wherein said mounting means are adapted to cause an upward movement of said attachment upon pivotal movement thereof in either direction from a given position relative to said vehicle in a manner whereby the weight of said attachment will tend to produce a centering movement about said vertical pivotal axis.

11. An attachment as set forth in claim 9 in which said core engaging member comprises a substantially cylindrical plug having its longitudinal axis extending at an angle to said other member.

12. An attachment according to claim 9 wherein said member for engaging the outer portion of a roll comprises a resilient plate having the contour of a cylindrical segment.

13. An attachment for a vehicle such as a lift truck adapted to handle cylindrical rolls having an open central core, said attachment comprising a flexible member having the contour of a cylindrical segment for engaging the outer surface of a roll, a back-up member for said flexible member comprising a rigid segment adapted to reinforce the central portion of said exible member, a sleeve for mounting said attachment on a vertical axis, a shaft ixedly secured to said back-up member and passing through said sleeve, said shaft including an abutment member xedly associated therewith and adapted to bear against the upper end of said sleeve, a member for engaging the core of said roll, uid pressure actuated mechanism for moving said core engaging member toward and away from said cylindrical segment member whereby said roll can be frictionally engaged therebetween, said shaft and said sleeve providing for a limited articulation of said attachment relative to said vehicle on said vertical axis in response to contact between said cylindrical segment member and a roll.

14. A device of the class described having supporting structure including a backplate member adapted to engage a surface of an article to be handled, article grabbing means extending outwardly from said backplate and comprising a tubular guide member, a pistonlike member slidably carried within said guide member, an article grabbing member depending from said pistonlike member and extending through a slot formed in said guide member, and a uid pressure actuating cylinder and rod assembly mounted within said guide member, one end of said cylinder and rod assembly being connected to said pistonlike member and the other end thereof to the said supporting structure of said device.

15. A device of the class described having supporting structure including a backplate member adapted to engage a surface of an article to be handled, article grabbing means extending outwardly from said backplate and comprising a guide member, a member movably supported by said guide member, a grab member carried by said movable member and'depending downwardly therefrom, and a liuid pressure actuating cylinder and rod assembly having one end connected to said movable member and the other end to the said supporting structure of said device.

16. The invention set forth in claim 15 wherein the article engaging surfaces of said backplate and said grab member are provided with anti-slip means.

17. A device of the class described having an upright supporting member, a backplate member adapted to engage a surface of an article to be handled pivotally carried by said supporting member on a substantially vertical pivotal axis, article grabbing means extending outwardly from said backplate and comprising a guide member, a member movably carried by said guide member, a grab member depending from said movable member and a iluid pressure actuating cylinder and rod assembly connected between said movable member and the center of said pivotal axis.

18. An article handling device for a vehicle such as a lift truck comprising a supporting member adapted to be secured to such vehicle in a transverse position thereon, means carried by said mounting member providing a plurality of transversely spaced vertical pivotal axes, article handling mechanism including mounting means selectively engageable with one of said pivotal axes, aligning means extending laterally to either side of said mounting means and provided with means for contacting a surface of an article to be handled on at least one location spaced above the surface upon which the article is supported and spaced to one side of the pivotal axis on which said mechanism is mounted, said mechanism being movable about such pivotal axis in response to such contact, and said mechanism further including grab means initially positionable relative to an article by such pivotal movement of the mechanism for engaging said article after alignment of said mechanism therewith.

19. An article handling device for a vehicle such as a lift truck, said device comprising a plurality of article handling mechanisms each including an aligning member for engaging a portion of one surface of an article to be handled, a grab member for engaging a second surface of such article disposed oppositely to the surface engaged by said aligning member, means for moving said members toward and away from each other whereby an article can be engaged therebetween, and mounting means providing a plurality of vertical pivotal axes transversely spaced on said vehicle, each said handling mechanism being carried by one of said axes for pivotal movement of the said aligning and grab members thereof about such pivotal axis in unison in response to contact between such aligning member and an article.

20. A device of the class described having an upright tubular supporting member, a shaft pivotally carried by said supporting member, a backplate carried by said shaft, a guide member extending outwardly from said backplate, a member slidably carried by said guide member, a grab member movable with said slidable member and depending below said guide member, a fluid pressure actuating cylinder connected to said slidable member and anchored to said shaft, and means normally urging said shaft to one position of pivotal movement within said supporting member.

2l. An article handling device adapted to be mounted on the structure of a lift truck for generally vertical movement, said device being of the type having a supporting structure including a back plate, an article grabbing member mounted outwardly of said back plate and movable relative thereto, and wherein an article to be handled is engaged from above between said grabbing member and said back plate; characterized by means for controlling the relative position between said grabbing member and said back plate independently of vertical movement of said device, comprising a uid pressure actuated cylinder and rod assembly, one end of said assembly being operatively connected to said grab member and the other end of said assembly being anchored to said supporting structure, and means for mounting said backplate on a vertical pivotal axis located intermediate the sides thereof.

22. The invention set forth in claim 21 further characterized by said article grabbing member having an article engaging surface projecting toward said back plate relative to the remaining portion of said grabbing member.

23. The invention set forth in claim 21 further inelud- 9 ing means to prevent the release of an article from said device in the event of a failure of the engagement thereof produced between said grabbing member and said back plate by said uid pressure assembly, comprising a power actuated member mounted for movement under an article after the same has been raised off a supporting surface, and means for adjusting the position of said power actuated member in a generally vertical direction whereby said power actuated member may be placed at a distance beneath the lower surface of an article less than the length of said article engaged by said grabbing member.

24. ln combination with an article handling device of the type described wherein an article is adapted to be engaged from above between a back plate and a grab member and frictionally held by relative movement therebetween, means for preventing the release of anarticle in the event of failure of such frictional engagement comprising a safety member mounted for movement beneath the lower surface of the article after the same has been engaged and raised from a supporting surface, means for adjustably positioning said safety member vertically relative to said grab member, and means whereby said safety member may move freely in a direction toward said grab member from the position established by said positioning means.

25. The invention set forth in claim 24 wherein said safety member is positionable at a distance below the lower surface of an article less than the length of engagement of said grab member with such article, whereby said safety member and said grab member coact to retain said article in the event of failure of said frictional engagement.

26. The invention set forth in claim 24 wherein said safety member comprises an arm secured to one end of a generally vertically extending shaft carried by said device, means for oscillating said shaft, means permitting movement of said shaft vertically relative to said oscillating means, and means for positively limiting the lower limit of such vertical movement in one of a plurality of selectable positions.

27. The invention set forth in claim 21 wherein said back plate comprises a resilient member adapted to substantially conform to a portion of the contour of an article under the compressive force exerted by the fluid pressure assembly and said grabbing member.

28. In combination with an article handling device of the type described wherein an article is adapted to be engaged from above between a back plate and a grab member and frictionally held by relative movement therebetween, means for preventing the release of an article in the event of failure of such frictional engagement comprising a safety member mounted for movement beneath the lower surface of the article after the same has been engaged and raised from a supporting surface, means for positioning said safety member vertically relative to said grab member, and means whereby said safety member may move freely in a direction toward said grab member from the position established by said positioning means.

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